PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 287 



This differs from all other hairy or spiny Chitons, at all nearly related 

 to it, in the mantle ornaments not being inserted into sockets, but being 

 extensions of its substance. 



24. (i7e>«^?/<i7/t« Cpr. MS., non Binney.) Nuttallina : zona lanngosa; 

 laminai centrales uniflssatae. This section unites in a form resembling 

 Nuttallina some of the features of Middendorjia, from which the girdle 

 differs in being spongy and covered with soft hairs instead of short 

 shelly bristles. The shape is that of an Ischnochiton, the sculi)ture and 

 girdle of Chojtopleura, the insertion plates and sinus almost exactly like 

 Middendorfia. Type PaUochiton lanuginosus Cpr. sp. Lower California. 



2Qa. Fannia Gray, not Eobineau Desvoidy, 1830. 



29. Lorica Acanthopleurse, zona Enoplochitoni similis; laminae obtusse, 

 pectinatie, sinus undatus, levis. Type Sclerochiton Cpr. Torres Straits. 

 Mus. Cuming, no. 42. 



Most like Unoplochito7i, from which it differs in the articulation of the 

 tail plate and the sub-central mucro. 



30rt. Lucia Gould, not of Swain son, 1833. 



30c. Acanthopleura : valvis partim iramersis,planatis; laminis centrali- 

 bus pleurifissatis; sinu lobato. Type Chiton spinosa Brugiere. 



This form bears the same relation to Acanthopleura that Fannettia 

 does to Tonicia, with the additional peculiarity of Eadsioid nicks in the 

 central valves. Named for Dr. Francis, once editor of the Annals and 

 Magazine of Natural History. 



31. Lorica solidissima alata: mucro hand elevatus submedianus; lam- 

 inae vulvae separatae, acuta?, leves; V. post, antice tendentes; sinus mini- 

 mus; :ona coriacea, fasciculatim spinulosa. Type Chiton gigas Chemnitz. 



32. Dawsonia C])r. (preoc.) 1873; Middendorfia Cpr. in MS. later.) 

 Lorica et zona e^stus ut in Acanthopleura ; laminae acutae, extus rugosa, 

 suff'ultaB; sinus planatus hand laminatus. Type Chiton Polii Philippi 

 (non Deshayes), Dalmatia. Internally Ischnoid, externally Acanthopleu- 

 roid. 



32a. {Beania Carpenter, not Johnstone.) Lorica et zona inter Acan- 

 thopleuram et Ischnochitouem intermedia; mucro subinediaiuis; lam- 

 inae acuti, hand suff'ulti; zona squamis subsi^inosis striatis vix imbricata. 

 Type Chiton Rissoi Cuming, non Payr. C. pseudorissoi Cpr. MS., Malta. 

 Mus. Cuming, no. 51. 



34. Lorica tenuis; valvae undatae; mucro posticus, productus, laminae 

 acutae, leves; V. post, antice projectae, sinus planatus, laminatus, levis; 

 zona coriacea, levis, sen lanugata. Type Arthuria filosa Cjir., loc. incert. 

 Mus. Cuming, nos. 23, 38. 



This has the aspect of Cha^tople^ira externally in sculpture, but has 

 the tail plate like Nuttallina in its structure, and like Placiphora iu its 

 external appearance. 



30fl. yl«/acoc//?7on pars, Shuttleworth, 1853. Lorica: mucrone postico, 

 parum sinuato; smu lobato; zona squamulis minimis obsita, antice [)ro- 

 ducta. Example, Lorica Angasi H. Adams, P. Z. S., 1864, p. 193. Aus- 

 tralia. 



